there are 3 things that you need to do to make this work:
1) create the script, use the above script from the community guide and paste into notepad. Save it as myownhud, then change the file extention to .fpi
2) create your .tga file and put it in the languagebank/english/gamecore/text called myownhud.tga
3) Put a trigger zone in your map, change the properties, main script should be myownhud.fpi (the one you created) and as long as the .tga file is in the right place it will appear,
See screenie attached for example
Far too new to be helping...